Asymmetric hybridization in (Odonata: Cordulegastridae): Secondary postglacial contact and the possible role of mechanical constraints.

Two dragonflies present in Italy, the Palaearctic and northern distributed and the endemic to the south of the peninsula , meet in central Italy and give rise to individuals of intermediate morphology. By means of mitochondrial and nuclear markers and of Geometric Morphometrics applied to sexual appendages, we defined i) the geographical boundaries between the two species in Italy and ii) we determined the presence, the extent, and the genetic characteristics of the hybridization. Genetic data evidenced asymmetric hybridization with the males of able to mate both interspecifically and intraspecifically.